Cadillac Repair: a/c, service bulletins, cadillac escalade

Question
My 2000 cadillac escalade now blows cold air for about 6 hours of an 8 hour trip.  It will suddenly start blowing HOT air and no matter how i set the climate controls it will continue to blow hot air.  After about 30 minutes of no a/c I can turn the a/c back on and get cold air for a while.  local shop no help, they just want to start replacing parts.  I can sense a disaster coming on.  thanks   rick

Answer
Hi Rick,

     I haven't come across this one yet and I understand your concerns. I don't have access to service bulletins until monday so I will look it up at work and if there is a bulletin then I will send you a message monday night. Until then the best advice I could give would be to go to the dealer and using all their resources might be able to give the fix. BUT I wouldn't replace any parts unless the assurance that they will be removed and you not charged if they don't fix the problem. Bill